This invention relates to humidification devices, particularly centrifugal humidifiers.
Various types of humidification devices have been developed to add moisture to dry air. In certain industrial and commercial environments, centrifugal humidifiers are often used. In such devices, water is propelled outwardly by a rapidly rotating plate or other body to impinge on a surface where it is broken up into small droplets that are entrained in a stream of air and then discharged to the surroundings.
Although the discharged air has a higher moisture content, the size of the droplets produced on the impingement surface of known centrifugal humidifiers is generally not sufficiently fine to be readily absorbed by the air. Instead, such humidifiers tend to produce a mist-like discharge. Not only does this result in a less than optimum overall humidity level, it also tends to create water build up on the surfaces of walls, equipment, furniture and so forth in the vicinity of the humidifier. More than merely an inconvenience, this promotes the growth of moulds and other microorganisms that can pose health risks to workers in the area.
Known centrifugal humidifiers are also limited in their throughput and efficiency. While increased humidification can be obtained by using larger humidifiers, or by using more humidifiers, doing so increases energy consumption and heat generation from the electric motors that are generally used to drive such centrifugal humidifiers.
Known centrifugal humidifiers also have a tendency to become clogged with dust and other particles when they are used in industrial environments such as textile mills.
It is a general object of the present invention to obviate or mitigate these and other disadvantages of known centrifugal humidifiers.
In accordance with the present invention, there is provided a centrifugal humidifier having a dish or other body rotatable on an axis for propelling supplied water outwardly by centrifugal force onto an impingement surface, generally concentric to the axis of the rotatable body, which breaks up the outwardly propelled water into fine droplets. The humidifier of the present invention also has means to intake a stream of air for entraining the fine droplets of water and thereafter to discharge the stream of air to the surroundings.
The impingement surface of the humidifier of the present invention has a multiplicity of sawtooth ridges. The ridges are each defined by a broader, more gradually inclined first side that faces toward the direction of rotation of the rotatable body, and a narrower, steeper second side that faces away from the direction of rotation of the rotatable body.
Because of the sawtooth profile, the water tends to hit and bounce repeatedly on the first sides of successive ridges which promotes breaking up the water into finer droplets that are readily absorbed by the stream of air. The centrifugal humidifier of the present invention can therefor produce a fog-like discharge, rather than the mist-like discharge of known centrifugal humidifiers. This greatly reduces the problem of wetting nearby surfaces, and also greatly increases the throughput the efficiency. The invention eliminates or reduces the need for filters or similar moisture eliminators which are commonly used in known centrifugal humidifiers to reduce wetting, but which also tend to reduce efficiency by screening out the finer water droplets as well as the larger ones. The sawtooth ridge impingement surface of the present invention also resists buildup of dust and other particles that can clog other centrifugal humidifiers.
Preferably, the centrifugal humidifier of the present invention includes a fan to take in and discharge the stream of air, and also includes a motor for driving the fan and for driving the rotatable body. Advantageously, the centrifugal humidifier of the present invention includes as well a water reservoir, and the rotatable body is generally bell shaped, with a broader flared rim and a narrower, cup-like lower portion immersed in the reservoir, such that rapid rotation of the body causes water in the reservoir to rise up the outer surface of the body to its rim from which it is propelled outwardly onto the impingement surface.
Most preferably, the centrifugal humidifier of the present invention also has a pump and conduit for delivering additional water from the reservoir to the inner surface of the rotating body.
It has been found that the centrifugal humidifier of the present invention provides an effective solution to obviate or mitigate problems presented by known prior art centrifugal humidifiers, as described above.